Police in Columbia, Mo., are looking into re-opening a 13-year-old murder case this week after the man once convicted of the crime walked free.

Ryan Ferguson left the Boone County prison a free man after nearly a decade behind bars for the killing of Columbia Daily Tribune sports editor Kent Heitholt in 2001.

Ferguson's conviction was vacated by an appeals court that found the prosecutor in his trial had withheld evidence. Witnesses who once said he committed the crime recanted their stories.

Ferguson, 29, has always maintained he didn't do it.

"As you can see," Ferguson said Tuesday after he was set free, "really, to get arrested and charged for a crime you didn't commit, it is incredibly easy and you can lose your life very fast, but to get out [of prison] it takes an army."

"The Department is reviewing the available options internally as to how or whether or not to proceed with additional investigation and/or a review of the case," police Chief Ken Burton said in a statement released Wednesday.

"Once a decision is made, I will release additional information. As always, we will continue to accept new information from anyone who is willing to come forward," he said.

The department's spokeswoman, Officer Latisha Stroer, added that the department is working with the city attorney's office to determine whether the case needs to be officially re-opened.

The murder case has been a mystery in Columbia since it occurred in 2001, when the sports editor was slain at a gas station around 2:30 a.m., according to a timeline compiled by Columbia news station KSDK.

No witnesses saw the crime take place, but two employees of the gas station saw two men near Heitholt's car and gave police a description of one of the men.

Ferguson, then 17, and his high school classmate Chuck Erickson had left a Columbia bar earlier in the morning, around 1:15 a.m., according to KSDK. Ferguson maintained that he drove Erickson home and then went home himself.

Years later, Erickson said he had visions that he believed to be memories in which he and Ferguson killed Heitholt the night after leaving the bar. Erickson agreed to testify against Ferguson in exchange for a lighter sentence.

In 2004, Ferguson was convicted of the crime in a five-day trial.

Later, Erickson recanted his testimony, along with the employees from the gas station, who say they were pressured to testify the way they did by the prosecutor.

After years of appeals, Ferguson was freed this week and the Missouri Attorney General said they would not seek to retry him.